Measurement of cardiac output and shunts
John Edward Boland, David W. M. Muller in Interventional Cardiology and Cardiac Catheterisation, 2019
An example of how to calculate CO by the Fick method is shown in the following. The following data were collected from a patient, and blood samples taken from the left ventricle (LV) and pulmonary artery (PA). Height: 152 cm; Weight: 50 kg; Age: 68 y Sex: Female.Body surface area (BSA): 1.45 m2.VO2: 200 mL/min.Hb: 12.5 g%.Body surface area is used to calculate cardiac index and other derived haemodynamic variables.Hb concentration is needed to calculate the O2 carrying capacity of blood (O2 capacity = Hb concentration × 1.36).O2 saturation of arterial and mixed venous blood is used to calculate the O2 content of each sample.The O2 content is used to calculate the A-V O2 content difference (CA – CV).
In Vivo Cardiac Measurements in the Conscious Rat
John H. McNeill in Measurement of Cardiac Function, 2020
Since the heart is a pump, to obtain a more quantitative picture of cardiac performance, cardiac output should also be measured. For example, following an experimental acute myocardial infarction, it is possible for left ventricular end diastolic pressure to increase while cardiac output is maintained by compensatory mechanisms. However, it is also possible to see a large fall in cardiac output along with an increase in left ventricular end diastolic pressure during experimental acute myocardial infarction. Clearly then, it is also important to monitor cardiac output along with intracardiac pressures when performing cardiac research. Measuring cardiac output is of particular value in chronic heart disease, as it is a primary indicator of the stage of the disease. That is, as the disease progresses, cardiac output will progressively fall. Indeed, cardiac index, which is cardiac output divided by surface area, is one of the main parameters used to determine whether a patient requires cardiac transplantation.
Methods and Procedures
Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin in Brain Injury and Pediatric Cardiac Surgery, 2019
In the first 24 hours, when frequent assessments of myocardial performance required uniform management, medications for hemodynamic support were standardized as described below. After 24 hours, the acute effects of aortic cross-clamping, cardioplegia, and cardiopulmonary bypass had resolved, and management decisions were made according to our routine practice.11 Detailed protocol for ICU management in the first 24 postoperative hours was as follows: All patients arriving in the Intensive Care Unit received Dopamine at a minimum of 5 µg/kg/min.There was a standardized infusion of Fentanyl at 5 to 10 µg/kg/h for at least 12 hours following cessation of cardiopulmonary bypass. Patients also received neuromuscular blockade.Determinations of cardiac index and systemic vascular resistance were made using intracardiac catheters (pulmonary artery, right atrium, left atrium) placed during surgery. Cardiac index was determined by thermodilution.Standardized treatments assumed that the clinical assessment of the patient correlated with the measured values of cardiac index and calculated systemic vascular resistance. Deviations from standardized treatment could occur at the discretion of the responsible physician.
Partial outflow pump dehiscence following off-pump HeartWare left ventricular assist device implantation in a patient with the Marfan syndrome
Published in Baylor University Medical Center Proceedings, 2019
Mina M. Benjamin, David L. Joyce, Asim A. Mohammed
A 30-year-old man with a history of MFS and worsening biventricular heart failure due to nonischemic cardiomyopathy presented to the emergency department in cardiogenic shock. Over the year prior to this presentation, he had had multiple admissions for heart failure exacerbations, with a progressive decline in his functional status as he progressed to stage D heart failure. His ascending aorta was dilated with a maximum dimension of 4.05 cm and Z score of 2.85 (Devereux). The patient was started on inotropic support. Right heart catheterization revealed a cardiac index of 1.5 to 1.8 L/min/m2. Given his worsening renal function on inotropes, a decision was made to move forward with temporary mechanical circulatory support using an axillary Impella 5.0 device. The patient’s subclavian artery was small and somewhat friable, but it was acceptable for applying an 8-mm chimney skin graft onto the right subclavian artery.
Proportional pulse pressure relates to cardiac index in stabilized acute heart failure patients
Published in Clinical and Experimental Hypertension, 2018
Colin J. Petrie, Piotr Ponikowski, Marco Metra, Veselin Mitrovic, Mikhail Ruda, Alberto Fernandez, Alexander Vishnevsky, Gad Cotter, Olga Milo, Ute Laessing, Yiming Zhang, Marion Dahlke, Robert Zymlinski, Adriaan A. Voors
In a cohort of HF-REF patients, a low PP had adverse prognostic value, if SBP < 140 mmHg (17). When EF is <30%, there is a linear relationship between SBP and outcome; higher BP is better. When EF is ≥30% but <50%, the relationship is “U” shaped (18). To adjust for systolic blood pressure, we examined PPP and its relationship to CI. Higher heart rates were seen with lower PPP; a shorter time for left ventricular filling may lead to a lower stroke volume and thus lower PPP. A lower stroke volume may also lead to a compensatory increase in heart rate to achieve an increased cardiac output. The association between low cardiac index and renal function is most likely based on low renal blood flow (19–21). The lower EF in the lower two tertiles of PPP (28/29% vs 42%; p = 0.0008) is expected and reflects more impaired cardiac function with lower PPP. This was less evident across CI tertiles. Treatment with serelaxin did not interact with the correlation between PPP and CI but was related to an increase in PPP (Figure 3). This may reflect haemodynamics of serelaxin (reduction of PCWP, SVR, and NT-pro BNP and improved renal function (11,22,23). Overall, serelaxin showed no statistically significant effect on the peak change and individual time point change in CI vs placebo.
Beyond thrombocytopaenia, haemorrhage and shock: the expanded dengue syndrome
Published in Pathogens and Global Health, 2018
Senaka Rajapakse, Milanka Wattegama, Praveen Weeratunga, P. Chathurani Sigera, Sumadhya Deepika Fernando
Transient myocardial depression has been described among children as well as adults in several prospective studies in Asia [5,20–22]. This phenomenon has been observed mainly during the toxic phase. The frequency of reduced ejection fraction was significantly higher in dengue shock syndrome and dengue haemorrhagic fever than dengue fever [21]. Mild to moderate reduction in ejection fraction has been detected by echocardiography as well as more specific radionuclide ventriculography, with mean values of 47.06% and 41.69%, respectively [22]. This myocardial depression is a attributed to a functional impairment, as 99m Tc pyrophosphate imaging did not show myocardial necrosis [22]. In an observational study among children, it was noted that patients with low ejection fraction required more aggressive fluid replacement, and low ejection fraction was associated with larger pleural effusions and respiratory embarrassment [23]. Apart from ejection fraction, end diastolic volume and cardiac index were found to be low. In addition, reduced systolic myocardial septal velocities and right ventricular systolic and diastolic velocities have been detected, in a study done in Vietnamese children [21].
Related Knowledge Centers
- Cardiogenic Shock
- Heart Rate
- Stroke Volume
- Ventricle
- Cardiac Output
- Hemodynamics
- Body Surface Area
- Intensive Care Medicine
- Coronary Care Unit